Issue #2315613 by damiankloip, Wim Leers: Add a services.local.yml for development.

core/core.services.yml

@@ -38,10 +38,6 @@ services:
     class: Drupal\Core\Cache\ApcuBackendFactory
   cache.backend.php:
     class: Drupal\Core\Cache\PhpBackendFactory
-  cache.backend.memory:
-    class: Drupal\Core\Cache\MemoryBackendFactory
-  cache.backend.null:
-    class: Drupal\Core\Cache\NullBackendFactory
   cache.bootstrap:
     class: Drupal\Core\Cache\CacheBackendInterface
     tags:

core/lib/Drupal/Core/DrupalKernel.php

@@ -526,8 +526,8 @@ class DrupalKernel implements DrupalKernelInterface, TerminableInterface {
         }
       }
     }
-    if (!empty($GLOBALS['conf']['container_yamls'])) {
-      $this->serviceYamls['site'] = $GLOBALS['conf']['container_yamls'];
+    if ($container_yamls = Settings::get('container_yamls')) {
+      $this->serviceYamls['site'] = $container_yamls;
     }
     if (file_exists($site_services_yml = $this->getSitePath() . '/services.yml')) {
       $this->serviceYamls['site'][] = $site_services_yml;

sites/development.services.yml

@@ -0,0 +1,9 @@
+# Local development services.
+#
+# To activate this feature, follow the instructions at the top of the
+# 'example.settings.local.php' file, which sits next to this file.
+services:
+  cache.backend.memory:
+    class: Drupal\Core\Cache\MemoryBackendFactory
+  cache.backend.null:
+    class: Drupal\Core\Cache\NullBackendFactory

sites/example.settings.local.php

@@ -10,6 +10,9 @@
  * mention 'settings.local.php'.
  */
 
+// Enable local development services.
+$settings['container_yamls'][] = DRUPAL_ROOT . '/sites/development.services.yml';
+
 // Show all error messages, with backtrace information.
 $config['system.logging']['error_level'] = 'verbose';
 
@@ -17,7 +20,8 @@ $config['system.logging']['error_level'] = 'verbose';
 $config['system.performance']['css']['preprocess'] = FALSE;
 $config['system.performance']['js']['preprocess'] = FALSE;
 
-// Disable the render cache, by using the Null cache back-end.
+// Disable the render cache, by using the Null cache back-end defined by the
+// development.services.yml file above.
 $settings['cache']['bins']['render'] = 'cache.backend.null';
 
 /**